Cold start problem 1990 Yamaha 70 2 stroke.

[Polar770]

Hi, I have a 1990 Yamaha 70 which runs smooth and reliable as long as it is hot. It starts immediately without problems as long as it is hot.
When it is cold on the other hand, I need to have a fresh, top charged battery to get it running.
The starterengine runs fast, but the engine is absolutely dead. I think it is an ignition problem. After 10 minutes of trying different positions of the throttle and choke it might suddenly start, and thereafter it is no problem.
Cold it be a stator or coil problem? Working bad as long as the engine is cold?

 

[robert graham]

Re: Cold start problem 1990 Yamaha 70 2 stroke.

my 1999 Yamaha 90C is the same way. be sure you pump the primer bulb up good before you start. what has worked with mine is on a cold start I crank on the motor for about 2 or 3 seconds and then stop cranking for a few seconds...then when I turn the key(with the choke on), it'll start right up. I've heard that each engine seems to have it's own little combination to get it going in the morning. When my engine is warm it's almost an instant start every time, like yours. good luck!

 

[rodbolt]

Re: Cold start problem 1990 Yamaha 70 2 stroke.

that 1999 90 is NOT like your 90 70.
that 1999 90 has prime start which only requires the operator to turn the key.,
your 1990 70 requires a bit of throttle opening AND choke.
make sure your choke works and try to fire it up at about 1500 RPM cold.
without a choke that 70 is tough to start cold.